Internal conduit sealing member and band

ABSTRACT

The present invention provides an internal conduit seal for conduits and pipes having an elongated elastomeric seal with first and second seal segments adjacent to the edges of the seal. The sealing segments are made up of a plurality of sealing ribs and restraining members placed externally of the ribs in each segment. The seal includes grooves positioned over each segment for expansion bands used to compress the seal against the inside of a conduit. The invention also includes an expansion band having a radiused contacting surface which in combination with a locking member of the invention positioned between an outer restraining member and an adjacent rib providing substantially improved sealing.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application of a application, Ser. No. 09/026,645,filed Feb. 20, 1998 and entitled “INTERNAL CONDUIT SEALING MEMBER ANDBAND”, now U.S. Pat. Ser. No. 6,126,206.

FIELD OF THE INVENTION

The present invention relates to an improved internal conduit sealingmember and in particular, to a sealing member made from an elastomericmaterial and having a pair of sealing segments located at the outerperiphery of the elastomeric seal which sealing segments includes aplurality of compressible ribs and inner and outer restraining members.Each rib segment is located under an expansion band to provide seals forpipe used in carrying various fluids. The invention also relates tonovel expansion band for compressing said internal sealing member and,in particular, to a radiused expansion band in combination with alocking element positioned between an outer restraining member andadjacent rib.

BACKGROUND OF THE INVENTION

It has become known to use cuffs or sealing members internally of aconduit to seal joints or damaged areas of a conduit to preventinfiltration into or leakage from the conduit or pipe. Conduits of thischaracter typically carry water, wastewater, sewage, natural gas,petroleum and the like. Since these pipe are normally locatedunderground, they are susceptible to damage from the environment,corrosion, cracking or leaks at the joints. In many cases it is notpossible to expose or excavate the pipe for repair because of thenecessary excavation would disrupt highways, building and the like. Inthese cases it has become acceptable to use trenchless, internal jointor damage sealing means. It is not uncommon to internally seal or repairpipes of diameters from 14 inches to 216 inches using elastomericsealing materials. See, e.g. U.S. Pat. No. 4,685,704. The seals areplaced within the pipes by skilled technicians who traverse the pipe tothe damaged or leaking area.

The sealing installation process is relatively uncomplicated. Theelastomeric seal generally is circular in nature, but can be dimensionedto assume other pipe shapes. The elastomeric material of the seal istypically selected for the type of material flowing through the pipe.For example, ethylene propylene diene monomers rubber is used for wastewater and potable water, butadiene acrylonitrile rubber is used innatural gas applications. Normally, the seal is provided with internalannular recesses designed to accommodate metal bands which are made fromstainless steel, carbon steel, or special alloys. Once the seal ispositioned over the joint or leak by hand or pneumatic means, the bandsare placed in to the annular grooves. A special hydraulic press is usedto expand the band in the groove to compress the seal against the pipe.Special wedges or inserts are used to maintain the position of the bandto maintain compression and provide a fluid tight seal.

Typically, the seals are manufactured by extrusion through a diecontaining the desired profile or molded, however, this is relativelyexpensive. The seal is extruded in the form of a belt with across-section in which the profile the sealing ribs located adjacent tobut spaced apart from the edges, and under the band accommodatinggrooves. A web membrane is located between the rib sections and can beof a varying lengths to accommodate both joints and areas subject todamage or leakage. The belt is cut uneven to fit the insidecircumference of the pipe, tube or tanks. Similarly, belts can be joinedby adhesive, overlapping or vulcanizing to form a continuous seal thatis circular or in other geometric shape.

While the use of internal sealing means such as disclosed in U.S. Pat.No. 4,685,704 afford more efficient and cost effective repair, suchrepairs are not inexpensive. It is therefore desirable to make therepair as well as the seal itself as trouble free and long lasting aspossible. Accordingly, it is an object of the present invention toprovide an internal pipe seal which can be installed using conventionalhydraulic presses and bands, but provides a sealing profile whichaffords more effective sealing than current seal profiles. It is afurther object of the invention to provide a novel seal, seal profile,and expansion band that locks in place when subjected to high velocityor low velocity flow of material transported through a pipe or struck bydebris moving within a pipe or conduit. It is also an objective of theinvention to provide an external seal member having a structure thatcontrols the cold flow of elastomeric material under compression of theexpansion bands.

SUMMARY OF THE INVENTION

The present invention comprises an internal conduit seal for sealing adamaged conduit or conduit joint which comprises an elongated molded orextruded elastomeric sealing member. Generally, the elastomeric memberhas a length which is substantially equal to the internal circumferenceof the conduit to be repaired and has a width adequate to accommodatethe span of the joint area which is damaged. Generally, however, theelastomeric seal member is not wider than about a meter since widerseals can be formed by overlapping multiple elastomeric members. Theelongated elastomeric member includes first and second spaced apartsealing segments that co-extend the length of the elastomeric member.Each sealing segment is positioned adjacent a respective edge of theelastomeric member and comprises a plurality of juxtaposed sealing ribsand an inner and outer restraining member. In the preferred embodimentthree parallel spaced apart longitudinal ribs are provided between theinner and outer restraining members.

The ribs in each of the first and second sealing segments depend fromthe base of the elastomeric member and terminate in a tapered endportion. In the preferred embodiment, the tapered end includes at leastone groove forming pair of substantially pointed sealing edges. In thepreferred embodiment, this groove is preferably “V”-shaped approximately2.5 mm in depth. However, if more than one groove is provided, that istwo or more, the depth of the grooves on a rib decrease in number withmultiple grooves the cross-section profile of the rib appears as aserration. The spacing between the ribs and the restraining members issuch as to permit the cold flow of elastomeric material duringcompression. The respective restraining members depend from the base ofthe elastomeric material a distance which is preferably slightly lessthan the ribs. The end portion of the restraining members are preferablyarcuate, but may have other shapes such rectangular or flat.

Positioned along the length of the elastomeric member and on the reverseside of the sealing segments and substantially overlying the respectivesealing segments are first and second associated band grooves. Theassociated grooves are dimensioned to accommodate expansion bands in aflush compressive fit. In practice, conventional expansion bands can beused. However, the present invention provides a radiused expansion band,which can be used in combination with the locking element of anotherpreferred embodiment.

In one embodiment of the invention, a continuous or segmented lockingelement is positioned in the space, between the outer restrainingmembers of each sealing segment and the associated first adjacent rib tosuch restraining member. Preferably, the locking member comprises aspring wire having knurled or edged sections along its length. Thediameter of the locking element if circular or oval or its depth ifrectangular or a polygon is less than the uncompressed height of the ribbetween which it is juxtaposed. The locking element provides gripbetween the elastomeric seal member when in compression and the conduitso as to resist movement when in the sealing position. In thisembodiment, it is particularly advantageous to utilize the radiused orconvex expansion band. With such use the force vectors through the sealssegments forces the locking element into the seal member and almost alocking engagement with the conduit.

In another embodiment, arcuate edge elements are molded or extrudedalong the length of each edge of the elastomeric member. The arcuateedge elements are formed with an outwardly extending flange and anarcuate return adjacent to the respective outer restraining member. Thearcuate extension is designed to extend outwardly from the body of theelastomeric member under compression of the latter during installationto form tapered surface from the conduit to the surface of theelastomeric member having the expansion bands. In this manner a smoothflow profile is present to provide a substantially laminar flow offluid.

The sealing member of the present invention provides a substantiallyenhanced seal means for internal sealing of conduit. In addition, theinvention is cost effective in providing long term protection againstfurther leakage. Other advantages of the present invention will becomeapparent from perusal of the following detailed description of presentlypreferred embodiments of the invention taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional elevation of one-half of the conduit seal of thepresent invention;

FIGS. 2a and 2 c are sectional elevations of the embodiment shown inFIG. 3 having various widths.

FIG. 2b is a sectional elevation of embodiment shown in FIG. 4.

FIG. 3 is a sectional elevation of another embodiment of the presentinvention illustrating a tapered edge member;

FIG. 4 is a sectional elevation of the another embodiment of the presentinvention illustrating the use of locking element in the embodimentdisclosed in FIG. 3 and a cross-section of the novel radiused expansionband;

FIG. 4(a) is a perspective cut away view of the seal and compressionband in a pipe joint; and placement of expansion band to compress theconduit sealing member against an area of a conduit experiencing leakageor infiltration.

PRESENTLY PREFERRED EMBODIMENTS

Referring to FIG. 1, an elongated elastomeric member 10 is shown insection. Depending upon the application elastomeric member 10 can bemade from a synthetic rubber such as ethylene propylene diene monomer orbutadiene acrylonitrile. Elastomeric member 10 includes a first surface11, and a second surface 12, compression surface, extending the lengththereof. Depending from first surface 11 are first and second sealingsegments 13 and 14. Sealing segments 13 and 14 are spaced from edges 16and 17 (not shown), respectively, of elastomeric member 10 as shown inFIG. 2A. In the preferred embodiment of the invention, each sealingsection comprises three spaced apart ribs 21, 22, and 23. As shown, ribs21, 22, and 23 depend from first surface 11. Each rib includes parallelsides a and b which terminate in angled end members c and d,respectively. Preferable end members c and d are positioned at an angleof approximately 60° to the horizontal, but angles from about 30° to 50°are usable.

Each rib also includes at least one groove or channel e, preferably“V”-shaped at 30 to 60° angle. Each channel or groove may also bearcuate. Each channel or groove forms at least a pair of apexes orpoints f and g which substantially compress during installation of seal10 to provide enhanced grip and elastomeric cold flow to provideimproved sealing and longevity under the compressive force provided byexpansion bands.

Each sealing segment 13 and 14 also includes an inner and outerrestraining member 31 and 32, respectively. Each restraining member hasparallel side walls x and y and arcuate end z. The height of therestraining members is slightly less than that of ribs 21, 22 and 23,e.g., 1 to 1.5 mm. Outer restraining members 32 are positioned adjacentto but spaced apart from sealing edges 36 and 37, respectively, ofelastomeric member 10. Elastomeric member 10 also preferably, includestapered ends 38 and 39 which terminate at edges 36 and 37, respectively.

Generally, the width between edges 36 and 37 is preferably about 29.2cm. Seal 10 also includes a pair of associated band grooves 26 and 27designed to accommodate an expansion band. Band grooves 26 and 27 areformed in surface 12 over associated rib segments 13 and 14. The area 41between segments 13 and 14 can be from about 25 cm to 61 cm. Area 41comprises the containment area for containing any leakage from theconduit that is to be sealed.

Referring to FIG. 3, another embodiment of the invention is shown inwhich like elements bear the same reference numerals as in FIG. 1,except that they are preceded by the numeral “3”. In this embodiment,elastomeric member 310 includes an inner surface 311 and a secondsurface 312. Band grooves 326 and 327 (not shown) are provided onsurface 312 to accept an expansion band, not shown.

Sealing segment 313 includes ribs 321, 322 and 323, preferably having apair of grooves or channels e1 and e2 as shown. Inner and outerrestraining members 331 and 332 are provided. In this embodiment, edges336 and 337 (not shown) are extended downwardly and outwardly from firstsurface 311 of elastomeric member 310. On the side of tapered edge 338is arcuate extension element 339. Arcuate extension element 339 has along radius, e.g. 25 cm to 30 cm and preferably about 28 cm, to providea counter flexure upon compression of the seal by extension bands. Inaddition, edge 336 is extended to effectuate a smooth transition fromthe conduit surface to conduit surface over surface 312 of elastomericmember 310.

Referring to FIGS. 4 and 4a, another embodiment of the invention isshown. In this embodiment, a locking member 409 is shown. Locking member409 is positioned between the outer rib 423 and the outer restrainingmember 432 of sealing segment 413 and 414. Locking member 409 ispreferably round polygonal in cross-section and co-extensive with thelength of the elastomeric member 410 either continuously ordiscontinuously which may include tapered end 438. Locking member 409may be made from stainless steel or other material which will not flowunder compression from expansion bands 408 placed in and of a length andwidth co-extensive with grooves 426 (427 not shown) (see FIG. 4a). Steelwire is the preferred material and it is further preferred that theouter surface be knurled or provided with edges to grip the surface ofthe conduit when elastomeric sealing member 410 is under compression.Locking member 409 is particularly effective when used in conjunctionwith compression band 408. Band 408 has a flat side 440 an inwardlyradiused or concave side 407 with radiused portions 441 of a radius fromabout 30 cm to 75 cm, which during compression places a downward forceon restraining member 432 to force it inwardly towards rib 423.Elastomeric member 410 is shown in FIG. 4 prior to compression againstthe inside of a conduit.

For the locking member, it is also desirable to select configurationssuch as polygonal wire, which provides a deep biting edge to both theconduit and the elastomeric member 410. Clearly, other shapes andmaterial will work in this function provided that its cross-section, asshown in FIG. 4, is less than the height of rib 423 and outerrestraining member 432 by at least 40% to 60% and preferably 50%.

With respect to radius band 408 shown in FIGS. 2b and 4, it is desirablethat the radius be such that on compression of the band, its edges 406and 404 provide an initial force which is towards the outer and innerrestraining members 432 and 431, respectively, so as to cause each ofthem to deform inwardly towards the adjacent rib. Preferably the band408 is made from a steel or like metal with a relatively large radius,e.g., 40 cm to 80 cm preferably about 54 cm. By compressing therestraining members there is less ability under compression during useto have the confined cold flow.

Accordingly, the present invention provides an improved seal forinternal surfaces and joints of conduit. When internal seal 10 is placedinside a conduit pipe, it is self-supporting because of its profiledesign and a shore A hardness of the elastomer compound. Thefreestanding uncompressed internal seal will stay in place in contactwith the pipe wall and positioned over the damaged area or leaking jointwhile the two compression bands are loaded into the grooves provided inthe seal. The compression bands can be either those with a flatcross-section or with a radiused cross-section design in accordance withthe requirements of the application. When the compression bands areexpanded, their circumference increases pushing the seal tightly againstthe pipe wall and compressing the sealing protrusions of the invention.Greater expansion force causes the circumference of the band to increasethus increasing the compression force of the protrusions affecting anextremely tight seal on the surface of the pipe, conduit or structure.As the compression forces increase, the three ribs seal protrusionslocated in the center area of the five protrusions rib segments 13 and14 begin immediately to point, load and effect a seal. As they continueto compress, sealing energy builds and the elastomer hydraulically flowsfilling any voids both in the surface to be sealed and the area betweenthe ribs and restraining mean expelling all air and replacing the airwith hydraulically flowing elastomer. Further, the two outer restrainingmean 32 contact the conduit and build significant additional sealingforce and sealing surface contact with the conduit. As compressiveforces in these outermost restraining member increase, they not onlyincrease the sealing effectiveness of this design over the prior art,but additionally increase compressive density within their structureforming a dam or bulkhead preventing cold flow and thus sealing energyloss from the centermost seal protrusions. The result is that thepresent invention maintains not only high sealing energy, but a longerperiod performance time by controlling energy loss that would occurwithout the incorporation of the highly compressed outermost sealingmeans and restraining area.

While presently preferred embodiments of the invention have been shownand described, in particularity, the invention may be otherwise embodiedwithin the scope of the appended claims.

What is claimed is:
 1. An elongated expansion band for use in aninternal conduit seal, said expansion band comprising a flexibleelongated member of a length and width co-extensive of a band groove inan elastomeric seal and having inner and outer sides, where said innerside is substantially flat and said outer side is concave or inwardlyradiused.
 2. The improvement set forth in claim 1 wherein said radius isfrom about 30 cm to 75 cm.